Don't swap machines yet. You're giving up functionality for portability.
1. Internet/email. No advantage for upgrading on this.
2. HD movies. No advantage here, either.
3. iPhoto Management. Currently, 256GB SSD is adequate for many tasks, but you're going to need additional storage. You can either get an external drive, or upgrade the SSD to 512GB. I recommend the latter.
4. Standard office work. No advantage.
Many users find that 4GB RAM is fine; an upgrade to 8GB is best if you're juggling several applications, or if you have lots of desktop applications installed; and that's where the RAM is useful. (I have 8GB for the latter.)